CVE-2020-13558

What it actually does

Use-after-free condition in AudioSourceProviderGStreamer that permits arbitrary code execution when a malicious web page is rendered.

Why it matters to the business

Attackers can fully compromise user systems browsing the web with affected WebKitGTK versions, enabling theft of data, installation of persistent malware, or lateral movement; the flaw has been publicly exploitable for years with no vendor-supplied fixed package versions listed.

How an attack unfolds

An attacker hosts a specially crafted web page that triggers the use-after-free in the GStreamer audio source provider during page rendering; successful exploitation yields remote code execution and has been observed in campaigns associated with Candiru / SOURGUM / DevilsTongue and multiple Apple WebKit memory-corruption chains.

How to fix it

Upgrade WebKitGTK to a version containing the fix for the use-after-free (post-2.30.1 releases that address CVE-2020-13558); if packaged updates are unavailable, apply vendor backports or isolate affected applications behind stricter browser sandboxing and web filtering.

How to confirm the fix worked

Verify the installed WebKitGTK version is newer than the vulnerable release and test that the crafted proof-of-concept page no longer triggers the crash or code execution.

Typical attack path

1. Attacker prepares malicious HTML that exercises AudioSourceProviderGStreamer
2. Victim loads the page in an application using vulnerable WebKitGTK 2.30.1 or similar
3. UAF is triggered during media handling, corrupting memory
4. Attacker gains code execution and installs payload

How to detect it

Review web browser process crash logs and memory dumps for AudioSourceProviderGStreamer faults; correlate with network logs showing visits to previously unknown domains around the time of anomalous WebKit processes.

What your security team should do

• Immediately inventory all systems using WebKitGTK and prioritize patching given public exploit availability and multi-year exposure window
• Block or sandbox rendering of untrusted web content in applications dependent on the affected library
• Monitor threat intelligence for Candiru/SOURGUM activity leveraging WebKit memory issues